Nemesis: Nomad Series, Book 2

Commander Terra Rush has spent the last eight months mourning Gryffin, believing he died when his ship crashed. When he returns to her, broken and scarred from months of torture at the hands of the Foundation, it feels like a miracle - at first. His unpredictable mechanical side, reawakened by the brutality he endured as a prisoner, threatens to destroy him. He's lost the trust of the colonists. Has he lost part of himself as well?

Ares: Nomad, Book 1

Gryffin was the sole survivor of The Foundation's experimental project to transform human children into hybrid cyborgs - half human, half machine. The program failed and he was sent on a one way trip into The Outer Sector where he was left for dead. He has survived for 20 years by suppressing his human emotions and embracing his machine side.